This PDF file contains the front matter associated with SPIE Proceedings Volume 12187 including the Title Page, Copywrite information, and Table of Contents.

At the end of 2021, the ESO council approved the start of the construction phase for a High Resolution Spectrograph for the ELT, formerly known as ELT-HIRES, renamed recently as ANDES (ArmazoNes high Dispersion Echelle Spectrograph). The current initial schedule foresees a 9-years development aimed to bring the instrument on-sky soon after the first-generation ELT instruments. ANDES combines high spectral resolution (up to 100,000), wide spectral range (0.4 µm to 1.8 µm with a goal from 0.35 µm to 2.4 µm) and extreme stability in wavelength calibration accuracy (better than 0.02 m/s rms over a 10-year period in a selected wavelength range) with massive optical collecting power of the ELT thus enabling to achieve possible breakthrough groundbreaking scientific discoveries. The main science cases cover a possible detection of life signatures in exoplanets, the study of the stability of Nature’s physical constants along the universe lifetime and a first direct measurement of the cosmic acceleration. The reference design of this instrument in its extended version (with goals included) foresees 4 spectrographic modules fed by fibers, operating in seeing and diffraction limited (adaptive optics assisted) mode carried out by an international consortium composed by 24 institutes from 13 countries which poses big challenges in several areas. In this paper we will describe the approach we intend to pursue to master management and system engineering aspects of this challenging instrument focused mainly on the preliminary design phase, but looking also ahead towards its final construction.

Appropriate project costing for astronomy instrumentation in early phases is pivotal to support the process of acquiring suitable funding. It also sustains the effective project cost management and increases the chances of project success. The absence of a clear method to project costing in the industry might lead projects to be undertaken at below cost at the risk of compromising quality and performance, eventually resulting in onerous cost overruns, and in worst cases, in failure and loss of reputation. This paper explores the use of techniques from the Project Management Body of Knowledge PMBOK applied to the cost estimate from conceptual design through to completion of one of instruments proposed for the Giant Magellan Telescope: MANIFEST, a robotic multi-fibre positioner that enhances the capabilities of other instruments in the telescope and enables the use of the telescope’s full field of view. Whilst the accuracy of the cost estimate results cannot be asserted until the project reaches more maturity, the MANIFEST cost estimate has proven to be a useful tool for cost control, more efficient resource allocation and forecast, and decision enabling during the MANIFEST Conceptual Design Phase 1. The cost basis of estimate used establishes the starting point to measure the project costing efficacy and the baseline required for the future program costing updates.

We present the work on applying Model-Based Systems Engineering (MBSE) to the conceptual design of the MANIFEST multi-object fiber positioner for the Giant Magellan Telescope (GMT). We use MBSE early in the system lifecycle to help identify and document the MANIFEST system characteristics. The application of MBSE allows the discovery of potential problems and their solutions. In addition, the MBSE facilitates managing complexity, reducing technical risk, and performing risk analyses. First, we report the benefits of the modeling process in capturing the problem domain model and stakeholder needs. Then, present the model framework, systems modeling language, and software tool to accomplish our goals for MANIFEST. Next, we report on the MANIFEST architectural products, the structural and functional elements, associated mappings, and relationships, including the interfaces between subsystems and external systems. Then we discuss the model presentation and report generation to communicate design aspects to stakeholders. Finally, we conclude with remarks about the effectiveness of the MBSE approach for the MANIFEST conceptual design.

Detector modelling is becoming more and more critical for the successful development of new instruments in scientific space missions and ground-based experiments. Specific modelling tools are often developed from scratch by each individual project and not necessarily shared for reuse by a wider community. To foster knowledge transfer, reusability and reliability in the instrumentation community, ESA and ESO joined forces and developed Pyxel, a framework for the simulation of scientific detectors and instruments. Pyxel is an open-source and collaborative project, based on Python, developed as an easy-to-use tool that can host and pipeline any kind of detector effect model. Recently Pyxel has achieved a new milestone: the public release and launch of version 1.0 which simplified third-party contributions and improved ease of use even further. Since its launch, Pyxel has been experiencing a growing user community and is being used to simulate all kinds of detectors beyond the traditional Charged-Coupled Devices and CMOS devices, for example Microwave Kinetic Inductance Detectors (MKID) and Avalanche Photo Diode (APD) devices. We give a tour of Pyxel’s version 1.0 changes and new features including a new interface, parallel computing, and new detectors and models. We continue with an example of using Pyxel as a tool for model optimization and calibration. Finally, we describe an example of how Pyxel and its features can be used to develop a full-scale end-to-end instrument simulator.

The new era of Multi-Object Spectrograph (MOS) Survey projects, in particular WEAVE (on the WHT at the ING) and 4MOST (on VISTA at ESO Paranal), require complex data flow systems. These systems encompass the software development for target selection, fibre configuration and observation at the telescope front-end and spectral processing, spectral analysis and archiving at the back-end. The system must also include quality control procedures, signaling mechanisms and alert reporting to ensure optimal use of telescope time and scientifically robust data products. Key to ensuring a fully functioning data flow system by first light are Operational Rehearsals (OpR) which use simulated data in end-to-end tests of the entire system. The Cambridge Astronomical Survey Unit (CASU) has been integral in defining and coordinating these OpR efforts, in its role of providing the back-end data management and the spectral processing pipelines, for both WEAVE and 4MOST. The WEAVE OpR programme is complete and we await first light. The first two rehearsal stages (OpR1 and OpR2) of the 4MOST OpR programme are complete while the third, and most complex, stage will commence in 2022.

HARMONI is the Extremely Large Telescope visible and near infrared integral field spectrograph and will be one of the first light instruments. The instrument supports four operational modes called No Adaptive Optics (NOAO), Single Conjugated Adaptive Optics (SCAO), High Contrast Adaptive Optics (HCAO), and Laser Tomography Adaptive Optics (LTAO). These operational modes are closely related to the wavefront correction topology used to support the performance required for each of the science cases. By following a novel function model-based systems engineering (FBSE) methodology in conjunction with observing the software computer system golden rule of design; namely having tight cohesion within software modules and loose coupling between modules, a system architecture has emerged. In this paper, we present the design of the HARMONI Control System (HCS). Although this is not the first time (for example NACO on VLT and NIRC2 on Keck) that the adaptive optics required to correct the atmospheric turbulence is part of a general instrument design, and not tailored for a very specific science case, this will be the first instrument of this size and complexity in the era of extremely large ground-based telescopes. The instrument control design must be compatible with the ELT instrument control system framework while there is also an expectation that the adaptive optics (AO) real-time computer toolkit (RTC-TK) should be used for the realization of the AO real-time control software and hardware. The HCS is composed of the instrument control electronics (ICE), the Instrument Control System (ICS), and the AO Control Sub-system (AOCS). The operation concept of the instrument is also novel in that for each mode the instrument creates an instantiation of a virtual system composed of only the system blocks required to provide the selected mode of operation. Therefore, each mode supports a unique system composition in terms of hardware, software, and the sequencing of activities.

The Gemini Infrared Multi-Object Spectrograph (GIRMOS) is an upcoming Gemini instrument that will be fed by the future Gemini North Adaptive Optics (GNAO) system. A critical feature of GIRMOS is multi-object adaptive optics (MOAO), providing an additional component of correction to GNAO; this feature will not only provide exceptional science, but also act as a key demonstrator for future extremely large telescope instrumentation, which will greatly benefit from MOAO capabilities. GIRMOS houses both an Imager and Imaging Spectrograph; as such, it is capable of several observing modes that span a range of spectral resolutions, field-of-views and pixel samplings on their detectors. These observing modes enable GIRMOS to be a scientifically versatile instrument with a substantial suite of science programmes, encompassing cutting edge science that ranges from the high redshift universe down to objects within our solar system. Several notable driving science cases enable GIRMOS to provide unique and critical observations, unfeasible by any other ground-based facility while simultaneously being complementary to JWST. We present here a detailed flowdown of the GIRMOS driving science cases to individual subsystems of the instrument in the form of performance budgets. In particular, we derive subsystem requirements for both the spectrograph and imager from several key cardinal science cases. This derivation leverages an end-to-end model of the entire system, including AO-modelling, site and telescope considerations, instrument-specific characteristics such as flexure and vibration, and typical observing practices.

SHARK-NIR is a near-infrared coronagraphic camera designed to exploit the excellent perfomances of the LBT Adaptive Optics system SOUL. Its main science target its the detection and characterization of exoplanets. Second generation instrument of the LBT, SHARK-NIR left 5 years ago its paper and models realm to become a real working instrument. Its compact size is a consequence of the available volume and required stiffness, but shall not convince you of a simple opto-mechanical design, translating in requirements for all the interconnected fields of software, electronics, archiving, etc. In this paper we will report the main steps that drove SHARK-NIR to become a real instrument with laboratory validated performances and the upcoming path towards commissioning, focusing on the coordination, interfaces and interactions of all the different involved fields, expertise and institutes of the consortium as well as of the hosting telescope.

MORFEO is the Multi-conjugate adaptive Optics Relay For ELT Observations, formerly known as MAORY (Multiconjugate Adaptive Optics RelaY), designed for the ELT first light instrument MICADO. With the goal of being compliant to Reliability, Availability and Maintainability (RAM) requirements, we present the approach for the RAM analysis carried out for MORFEO at system level. RAM analysis allows to monitor the possible failures that could occur at lower levels and to highlight criticalities, hence leading to recommendations for design changes, thus preventing failure propagation at higher levels, and providing a maintenance strategy to keep the system in operation. The RAM process requires not only a series of interactions with all subsystem engineers, but also with AO specialists that identify all possible degraded modes that are a key aspect of failure assessment, but must be driven by requirements on science. The RAM approach we will outline is the base for having a more reliable design and for defining a suitable maintenance plan, with the final goal of enhancing the system availability, thus avoiding critical down time of the instrument during its entire lifetime.

Model-based systems engineering has as one of its central pillars the single source of truth that is usually a CAD model, or a model defined using a language such as SysML. However, having a single point of truth is not incompatible with using multiple modeling languages. A simple DSL like PORIS allows us to make instrument sketches much more concise and understandable than if we made them in SysML. By providing this language with transformers, we can automatically and instantly generate configuration panels, diagrams and documentation that allow the scientific team of the instrument to create more quickly and formally the configuration and functional specifications of the instrument. Engineers can also create a high percentage of the instrument software, for instance, the ones related to configuration, monitoring, diagnostics or safety. In this article we will show how, starting from a simple model in a spreadsheet, we will end integrating its software in the GTC control system.

We present the progresses of the simulation tools, the Exposure Time Calculator (ETC) and End-to-End simulator (E2E), for the Son Of X-Shooter (SOXS) instrument at the ESO-NTT 3.58-m telescope. The SOXS will be a single object spectroscopic facility, made by a two-arms high-efficiency spectrograph, able to cover the spectral range 350-2000 nm with a mean resolving power R≈4500. While the purpose of the ETC is the estimate, to the best possible accuracy, of the Signal-to-Noise ratio (SNR), the E2E model allows us to simulate the propagation of photons, starting from the scientific target of interest, up to the detectors. We detail the ETC and E2E architectures, computational models and functionalities. The interface of the E2E with external simulation modules and with the pipeline are described, too. Synthetic spectral formats, related to different seeing and observing conditions, and calibration frames to be ingested by the pipeline are also presented.

The Maunakea Spectroscopic Explorer (MSE) will target sources down to m_AB = 24 with a signal to noise ratio > 1 from the near UV to H-band. Among MSE’s many science goals, this will allow the efficient spectroscopic follow-up of large imaging surveys anticipated from new facilities such as the Rubin Observatory. Given broadband AR coatings currently feasible for large optics, this poses a unique challenge in terms of controlling contamination from optical ghost reflections. We present exploratory work to identify telescope designs with optical ghost levels that satisfy the observational thresholds required for MSE. We also report on an initial estimate of scattering from the optics that indicates that it will have a minor impact on the accessible sky, does not drive the telescope design selection, but must be accounted for in science/sky fiber placement. The outcome of these studies is that a range of telescope configurations exist that allow MSE’s target sensitivity to be reached without limitation from optical ghosts or scattering from the optics.

The Mid-infrared ELT Imager and Spectrograph (METIS) is among the first three scientific instruments commissioned at the ELT. It will implement vortex coronagraphy to achieve high-contrast imaging (HCI) at small angular separations from bright, nearby stars. An important unresolved problem with vortex coronagraphy is the vortex center glow (VCG) effect, where the thermal emission from the warm environment around the entrance pupil is partially diffracted into the image of the pupil by the vortex phase mask (VPM), which shows up as a diffuse bright spot in the center of the image. This effect has proven to be a significant nuisance in previous mid-infrared observations. Here, we use physical optics propagation to model the VCG for the first time and evaluate its strength with respect to the background flux in standard noncoronagraphic imaging in the context of ELT/METIS. Through our end-to-end simulations we find that the VCG peaks at about 70% of the standard background flux at an angular separation of 1 λ/D from the star and reduces to about 20% at 5 λ/D from the star. We apply the same method to model the VCG for the VLT/VISIR configuration, and show our model to be in agreement with the actual VCG measured in VISIR data, where the peak of the VCG is about twice as bright as the thermal background. In case the VCG turns out to be larger than anticipated in METIS, we propose two methods to mitigate it: (i) adding pupil stops in the pupil plane upstream to the VPM to block all of the thermal emission, and (ii) adding undersized Lyot stops in the image plane to block part of the diffracted light.

The High-contrast End-to-End Performance Simulator (HEEPS) is an open-source python-based software with a modular and extensible architecture, that creates end-to-end simulations of high contrast imaging (HCI) instruments. It uses the wavefront Fresnel propagation package PROPER, the telescope instrument data simulator ScopeSim, and the HCI image processing package VIP. In this paper, we present the design of HEEPS, and motivate its baseline structure with the implementation of the Mid-infrared ELT Imager and Spectrograph (METIS) HCI modes, including coronagraphic components such as vortex phase masks, ring apodizers, and apodizing phase plates. Then, we present the key results of our thorough end-to-end simulations starting from 1-hour AO residual phase screens produced with the end-to-end AO simulator COMPASS. We analyze various undesirable effects such as pupil effects (stability, uniformity, drift) and noncommon path phase and amplitude errors. Finally, the coronagraphic performance including all effects is shown for all the METIS HCI modes as 5-sigma sensitivity contrast curves after ADI post-processing.

The Rubin Observatory has entered its latter stages of the construction effort with system integration, test and commissioning. All system elements are coming together including components of the telescope, the science camera and software systems for control and data processing. In this paper we report on the progress, status, plans and schedule for integrating the system elements into a fully functional observatory to carry out the 10-year Legacy Survey of Space and Time.

AMOS has recently completed the on-site erection and performance evaluation campaign of the 2.5m telescope that is installed on Mount Abu (India) for the Physical Research Laboratory. The 20-m-focal-length telescope has a Ritchey-Chrétien optical configuration. It is equipped with a primary active mirror; an active positioning of the secondary mirror and a first order adaptive optical system. It operates in the 0.37-4 μm spectral range. The project fulfillment relies on the AMOS multidisciplinary expertise in design; manufacturing and verification of high-accuracy optical; mechanical and opto-mechanical systems. This paper presents the assembly; integration; alignment and verifications carried out on site. The alignment relies on the coma-free point method. The end-to-end telescope performances (image quality; pointing; tracking) are measured on sky using the verification instrument in combination with wavefront-curvature sensing and lucky imaging techniques.

The Microchannel X-Ray Telescope (MXT) is part of the Sino French SVOM mission mainly dedicated to Gamma-Ray Bursts (GRBs). MXT combines a “lobster-eye” focusing X-ray micro-pore optic with a pnCCD detector operating from 0.1 to 10 keV. A stable structure made of carbon fiber reinforced polymer (CFRP) and titanium connects the two parts and provides the interfaces with the satellite. After a short description of the instrument, this paper first presents the alignment process and the measurement of the line of sight (LOS) at MPEs PANTER facility in Germany. Then we focus on the prediction of the in-orbit LOS stability combining thermos-elastic simulations and dedicated measurements.

The Giant Magellan Telescope project established Key Performance Parameters (KPPs) for measuring, tracking, and managing the evolution of expected observatory performance through construction and commissioning. The KPPs are inherently statistical variables. The performance of the as-built observatory depends on environmental and operational parameters. Just as importantly, its performance also depends on not fully predictable programmatic processes and technical uncertainties associated with design and construction. Mitigation of technical risks and management response to realized technical risks have critical impact on achieved performance through decisions allocating project resources to remedy potentially impaired performance. While the requirements capture the objective values of KPPs, relaxed threshold values represent the minimum acceptable performance that must be achieved in support of the scientific objectives of the observatory. Properly defined threshold values may reduce project risk exposure and aid project management in building and delivering the observatory on time and on budget. This paper reports our statistical approach to determine the KPP threshold values the project can accomplish with high confidence level in the face of programmatic and technical uncertainties. The method identifies the technical risks threatening KPPs and carefully characterizes them to ensure their suitability for further evaluation. This paper also demonstrates a Monte Carlo approach to using recognized project and subsystem risks to bound the probability density functions for performance, cost, and schedule impacts, which are in turn applied to each KPP error budget to determine threshold values. The analysis is integrated into the project’s statistical risk and contingency estimation framework.

The GMT strategy for advancing subsystem design using aerothermal modeling is presented. The focus is not on the models themselves but on the procedure used to answer specific questions posed to the GMT System Engineering Integrated Modeling team by the various subsystem groups. Work in progress from an aerothermal point of view will be presented in several major subsystems. The scheduling challenges and resource management, both computational and human, to ensure timely responses are also addressed.

The objective of the systems engineering effort is to ensure the successful development and operability of the TMT system, by defining clear policies and procedures for architecture definition, requirements management, interface management, integration management, and verification. This paper shows the tailored implementation of the systems engineering approach which is intended to ensure that the system meets all requirements while being affordable, producible, and maintainable over the observatory’s life, while maintaining acceptable risk. This paper also describes the evolution of this approach in the last decade at TMT and the reasoning behind that evolution.

The Thirty Meter Telescope is a large and complex system with thousands of optical, mechanical, electrical and electronic parts required for its operation. It is vital that the system operates reliably such that only a small percentage of time is lost to unexpected failures. The loss of time depends not only on the reliability of each part, but also how the system is designed to be robust against failure so that it can continue to operate in a degraded mode in the presence of a failure, and also how the operational model is designed to be adaptable so it can deal with unexpected failures. TMT has developed a reliability model that accounts for degraded operation of the telescope and a flexible operations model. An estimate of the system reliability has been made using this model, and the lessons learned in developing the model used to develop a straightforward method for suppliers to assess their systems susceptibility to failures and estimate the subsystem reliability.

The US Extremely Large Telescope Program (US-ELTP) is a joint endeavor of the National Science Foundation’s National Optical-Infrared Astronomy Research Laboratory (NSF’s NOIRLab) and the organizations building the Thirty Meter Telescope (TMT) and the Giant Magellan Telescope (GMT). Our goals are to complete construction of both observatories and to enable all US astronomers to carry out transformational research that takes full advantage of the diverse capabilities of both GMT and TMT as well as the two-hemisphere system. NOIRLab’s portion of this initiative is a software suite called the US ELT Program Platform (UPP). The UPP will support the investigator through all phases of their observations: from proposal creation, time allocation, observation data transfer and storage, and data analysis, to publication. NOIRLab is currently preparing for a 2023 NSF Preliminary Design Review (PDR). NOIRLab used previous ground-based astronomy project experience and lessons learned to tailor our requirements management processes and help downselect a requirements management tool. To increase stakeholder communication and collaboration during the requirements generation activities, we have taken a novel approach to requirements management for astronomy projects by using the Atlassian Jira [1] add-on called “Requirements for Jira” (R4J) [2]. All facets of requirements management are conducted within the Jira environment. This approach has proven to be exemplary as Jira provides an intuitive and collaborative environment with which most of the project staff are already familiar. This paper details the motivations and results of our requirements management tool trade study and provides examples of how the requirements management processes are implemented within Jira.

Technology development enables space flight missions. This paper reviews lessons learned for how to formulate and implement an intentional technology development process. We describe four elements of this disciplined approach. First, start with Science Driven Systems Engineering. Define the Level 0 science requirements and derive a science traceability matrix for required measurements. Technology innovation and maturation does not happen in a vacuum. It is tied to the fulfillment of well-articulated science goals. Second, study, analyze and develop multiple notional mission concepts to identify and prioritize technology gaps. Third, invest in the maturation of mid-TRL technologies. And fourth, consistent oversight of the efficacy of those investments. Technology grants, cooperative agreements and contracts need to have active and close management and reporting of their progress, milestones, TRL advancements and final outcomes, to meet the goal of promoting and increasing the technology infusion rates in future space flight missions. The cumulative value of lessons learned from flight projects and expertise gained in the last decade enables more effective ways to promote advances via an intentional technology maturation model, a significant variation of the classical pull technology model.

On the 18th January 2003 the devastating Canberra firestorm completely destroyed all of the Mount Stromlo telescopes, technology development workshops, much of the observatory infrastructure. The Advanced Instrumentation Technology Centre (AITC) was established (2006) in the aftermath as a world-class facility to support the development of the next generation of instruments for astronomy and space science. In this paper describe the integrated portfolio, project, quality and system engineering management processes, that have been implemented in order to operate the AITC as a primarily financially self-supporting, University based, instrumentation centre within the highly volatile and rapidly evolving business landscape of today, i.e. what has helped the AITC to survive, and even thrive, during the highly turbulent years, also what has been developed, evolved, strengthen and even eliminated from our structure and operational practices.

Projects supported by culturally and geographically diverse teams need robust tools that achieve scientific and technical deliverables through real-time collaboration and effective document management. Given limited resources, the optimal mix of tools is cost-effective, succinct, flexible, and intuitive. It enables all phases of the project, and it facilitates the creation of a comprehensive set of documentation to support science operations. The Maunakea Spectroscopic Explorer (MSE) is an international project with scientists and engineers working in different time zones across the world. MSE’s unified approach to project control and facilitation integrates the software platforms, manual processes, and project management tools used to develop project deliverables, which include a detailed set of configurable documents representing the project’s programmatic, scientific, and technical performance objectives. MSE’s Configuration Management and Reviews Plan (CMRP) defines those documents and describes the mechanisms by which the project controls their quality and integrity. Those mechanisms include MSE’s configuration management processes as well as the tools supporting those processes: software for collaboration, documentation, and project management; the MSE document naming and numbering system; the document index lists and version control process that trace the deliverables’ development throughout the life of the project; and project management tools, including a responsibility assignment matrix and document approval and release processes.

System engineering and project-team management are essential tools to ensure the project success and the Redmine is a valuable platform for the work organization and for a system engineered approach. We review in this work the management needs related to our project, and suggest the possibility that they fit to many research activities with a similar scenario: small team, technical difficulties (or unknowns), intense activity sprints and long pauses due to external schedule management, a large degree of shared leadership. We will then present our implementation with the Redmine, showing that the use of the platform resulted in a strong engagement and commitment of the team. The explicit goal of this work is also to rise, at least internally, the awareness about team needs and available organizational tools and methods; and to highlight a shareable approach to team management and small scale system engineering.

This paper derives an expression for the time to manufacture a large number of identical units under the conditions of finite server reliability and time to return to normal operations. The key parameters of the problem, server mean time between failure and mean time to restore operations are introduced and their impacts identified. The manufacture of x-ray optics is used as an illustrative example and a number of strategies to mitigate the impact finite server reliability are examined. The paper concludes with a set of next steps to improve the fidelity of this modeling and analytic effort.

The Caltech Submillimeter Observatory telescope (CSO) will be moved from Mauna Kea, Hawaii to Chajnantor Plateau, Chile in 2022, and renamed as Leighton Chajnantor Telescope (LCT). The altitude of the new site of LCT is 5050 m, and the average wind speed is about 10 m/s. However, the pointing accuracy of LCT will be improved to 1 arc-second (rms), and the rotating speed of LCT’s antenna will be improved to 2 degrees/sec, in order to achieve its new scientific aim of large survey in the sub-millimeter waveband. More precise pointing accuracy and faster rotating speed under higher wind speed makes the servo control of LCT very challenging, because both the steady-state and the transient performances of the servo control system are required to get improved under larger disturbance, while the mechanical structure of LCT is less rigid due to the adoption of lean and optimized design. To solve this problem, in this work, a state-space model of the LCT servo control system is constructed, and the Davenport wind disturbance model for LCT is also constructed for simulating wind disturbance. To improve the stability and controllability, a robust controller of the servo system is designed based on H∞ control theory with considering the disturbance of high wind speed. Simulation analysis verifies the capability of the designed controller for improving LCT’s pointing accuracy and its antenna’s rotating speed. This research is of good significance for the refurbishment of LCT and the achievement of its new scientific aim.

The Iranian National Observatory Telescope is a 3.4-meter Alt/Az optical telescope. MCS (Mount Control System) is developed in such a way that meets the requirements of movements control of all axis. To this end, the end-to-end (E2E) simulations are performed using Matlab software. In this simulation, the telescope is modeled with adequate precision, and the mechanical behavior of the model is tested. Then the results were confirmed with other software independently in some specific positions to make sure that the mechanical behavior is precise and valid. Then in the Matlab software, a controller is developed, and the simulated telescope is controlled. Tracking error is calculated with the presence of the simulated wind at the predicted speeds, and the performance of the MCS is then analyzed and the controller is improved. The tracking accuracy at different speeds is calculated and compared. The final controllers are tuned in Matlab, and errors and noises are applied in the simulation environment. A simple optical instrument is also simulated to estimate the image quality in the image plane. Then, after development of the structure of the telescope, in the integration phase, the appropriate controller is implemented in the real controller, and the real results are recorded from the telescope. During integration, a test camera is placed in the telescope to check the primary image quality and compare the results with the encoder's recorded data. In this paper, we discuss the design and development approach for axis controllers and provide the related results together with the future upgrades necessary for enhancing telescope performance.

The Nancy Grace Roman Telescope (RST) is a NASA observatory designed to unravel the secrets of dark energy and dark matter, search for and image exoplanets, and explore many topics in infrared optics. Scheduled to launch in the mid-2020s, this 2.4 meter aperture telescope has a field of view 100 times greater than the Hubble Space Telescope. The mission is currently in its construction phase, where integrated modeling between thermal, structural, and optical models of the observatory is necessary to demonstrate science quality images over the range of operational parameters. This presentation discusses the crosschecks used in the integrated modeling process for RST, including the various flows of data between the modeling disciplines, and summarizes the current predicted performance. Additionally, several optical modeling tools are discussed, along with the specific requirements they are meant to address.

Efficiently characterizing the relative differences in performance between early telescope design concepts is important when identifying individual concepts for further study. This paper presents a simulation-based model for the exploration of the design trade space of a space-based telescope in the presence of uncertainty. A systems framework is introduced that considers both multi-objective optimization and uncertainty quantification over the design space. The incorporation of uncertainty when exploring the trade space can help to identify concepts that are best suited for accomplishing a specific goal and can maximize the knowledge about a design early in the mission lifecycle.

The NRT is an international collaboration to design and build a leading astronomical facility in the optical and near infrared ranges for the emergent area of time domain astronomy. That relies on the combination of a large collecting area (4 m diameter), quick response (<30 s), and full robotic operation. The system level analysis and trade-offs for assessing image quality, defining optics and optomechanics requirements, integration of both, and expected performance are particular challenging issues for such segmented optical configuration. This contribution presents the methodology developed within the project to produce suitable optical and optomechanical models and measure their performance. This methodology optimizes system level parameter exploration and tradeoffs, quick regeneration of models after possible changes in the design, and integration between optical and mechanical analysis.

The responsibilities of the James Webb Space Telescope (JWST) Science and Operations Center (S&OC) include: observation proposal generation support, planning, and scheduling; Observatory health and safety monitoring, command data uplink and telemetry capture; data processing, calibration, archiving, distribution, and analysis; monitor and control of Observatory optical performance; and providing a reliable source of configured data for subsystem operations. Through a strategic set of goals, S&OC System Engineers have supported S&OC development and prepared the S&OC for Observatory commissioning and operations. These goals support the principle of ‘science systems engineering’ and are consistent with standard systems engineering processes.

The anticipated ubiquity of privately owned and operated satellite spacecraft in low-Earth orbits will revolutionize the space domain. Space is becoming increasingly commercialized with satellite technology promising technological advancements such as low-cost global internet access. While satellite constellations will likely boost the global economy and increase internet accessibility worldwide, they will also introduce foreground contamination which may greatly impede astronomical observations from the ground. This proceedings discusses the projected impact of the growing space industry on the field of astronomy. Optical, radio and microwave astronomy will be affected by commercial satellite constellations. While the prognosis for ground-based astronomy may be bleak, the expected upcoming prevalence of low-cost satellite technology may open new doors for astronomers within the next decade and beyond.

The TOU is the Telescope Optical Unit for the PLATO ESA mission, consisting of the opto-mechanical unit for each of the 26 Cameras of which PLATO is composed. The TOU is currently in the manufacturing, assembly, integration and testing (MAIT) phase for the Proto Flight Model (PFM) and for Flight Models (FMs). We present the design processes as seen from the Product Assurance (PA) point of view: PA aims at monitoring the design and addresses specific issues related to, among others, materials and processes (these shall be suitable for the purpose and for the life-time of the mission), cleanliness and contamination control (to limit the loss of optical performance), safety, monitoring of qualifications/validations. PA supports the project in failure-proofing aspects to mitigate criticalities, e.g. in the elaboration of non-conformances and deviations that can arise during the design and MAIT process, and/or are highlighted during the reviews for manufacturing, test, and delivery of the related hardware. PA ensures early detection of potential problems and risks for the TOU and arranges for corrective actions that aim at improving the likelihood of success of the mission.

We show the capabilities of transient Computational Fluid Dynamics (CFD) simulations in analyzing the flow field in large telescopes with accurate temperatures. For these demonstration simulations, a telescope spider structure of about 40 meters in diameter with numerous trusses is modeled and a transient fluid simulation is carried out in cross wind configuration. We simulate the flow behavior using a commercial Lattice-Boltzmann Method (LBM) based solver for its computational efficiency, the low numerical dissipation and its ability to track vortices along the size of the domain. In order to link temperature deviations ΔT to wavefront error (WFE), we integrate ΔT parallel to the optical axis and multiply by the refractive index gradient dn/dT = −700 nm/K/m, thus carrying out simple raytracing. The LBM is highly efficient, both in terms of structure geometry preparation and for the simulation itself and can easily solve the 3D time-resolved flow in a volume of 70×65×110 m³ over several seconds of physical time. The highest spatial resolution was 35 mm. Our study may enable targeted AO correction based on the measured wind vector.

The European Solar Telescope (EST) is a 4-m class solar telescope that will include a multi-conjugate adaptive optics system (MCAO) integrated in the telescope optical path. Currently, the EST is in its preliminary design phase, in which different alternatives for the main telescope subsystems must be proposed and evaluated to meet the main scientific requirements. The availability of models to predict the performance in this phase is therefore essential. A global end-to-end model including the main telescope structure control, the active optics system and adaptive optics strategy is planned for the EST. This document presents the in-house model developed to evaluate the dynamic requirements defined for the telescope structure during tracking operation. First, those requirements specified for the EST during tracking operation are presented. Then, the whole process to obtain and validate the dynamic representation of the telescope structure from the mechanical model is explained. Main dynamic loads likely to affect the tracking performance such as wind buffeting initially characterized for the EST are described. A controller is tuned for closed-loop axes control to ensure trajectory tracking while rejecting the wind effects. Finally, a Simulink model for the evaluation of the tracking performance including the main elements identified for the EST is proposed. Preliminary results based on simulations and their effects on the final telescope structure design are presented. In addition, possible implications on the tip-tilt control strategy to reduce residual image motion for an accurate image stability are analyzed.

ESO took a systematic approach at earliest phases of the ELT programme to address different aspects of vibration at the telescope, from modelling, error budgeting, requirement specifications, to envisaging verification and mitigation methods. Recent activities focused on measuring and characterizing the vibrational forces generated by typical equipment in the observatory. In addition, the measurements are performed to design and verify the efficiency of the required isolation systems. In this paper, a complete system analysis using these measurement data as input to the detailed model of the telescope structure combined with hosted units, i.e. mirrors, instruments and other equipment, (all at final design phase) is presented. The analysis serves as a verifying tool to observe the actual state of the performance versus the top-level budget. It is also discussed how the results are used for improving the design and envisaging the potential mitigation strategies.

The scientific performances of the Giant Magellan Telescope (GMT) Observatory are divided into Observatory Performance Mode (OPM) formally defined in the GMT Observatory Requirement Document (ORD) as a direct flow down from the GMT Science Requirement document (SRD). There are 3 main OPM categories: Natural Seeing, GLAO, and High Angular Resolution (e.g., NGAO, LTAO) that branched out into several sub-categories. For each OPM, system engineering has defined image quality metric standards: Key Performance Parameters (KPP) that acts as bounds to the Observatory overall performance within which design parameters are traded. During the course of the project, system engineering must assess the compliance of the current design solutions with respect to the KPPs. The GMT project has build an exhaustive integrated modeling computing framework allowing for bottom-up end-to-end modeling of the entire GMT Observatory. This integrated modeling framework brings together finite element, control, optical, thermal and fluid dynamics models. This paper introduces the integrated modeling framework and describes the whole process that is setting up bottom-up end-to-end simulations of GMT OPMs. For example, analytical error budgets and the project risk registers are used to identify and to down select the most relevant parameters and features of the telescope design that must be included into the GMT integrated model while keeping the size of the simulation manageable from a computing load standpoint. The paper also reports on how the model validation unfold with model audits at both system and subsystem levels using software management best practices. Finally, simulation results for several OPMs are presented and discussed in terms of their statistical meaning with respect to the foreseen on-sky estimation of the KPPs during the Assembly, Integration and Validation phase of the project.

Environmental effects on the Image Quality (IQ) of the Thirty Meter Telescope (TMT) are estimated by aero-thermal numerical simulations. This study summarizes the state of the art of optical turbulence modeling and presents an update of the ongoing effort to minimize prediction time and computational resources by extrapolating the convergence of TMT’s IQ metric in the spatial resolution limit with quantifiable uncertainty, in order to be able to conduct trade studies and assess IQ sensitivity to various thermal gradient inputs.

This contribution presents the structural analysis that followed the preliminary design specifications of the European Solar Telescope (EST). EST is a 4-metre class telescope based on an aplanatic Gregorian configuration with an alt-azimuthal mount. The optical design has undergone several changes since the end of the conceptual phase. A finite element model (FEM) was developed to verify the structural performance of the telescope with the new optical design. This model includes the elevation structure, the azimuth platform, the pier and the ground at the observatory site. Two different orientations of the telescope were modelled, pointing horizon and zenith. Dynamic modal analyses were performed to estimate the natural frequencies and mode shapes of the telescope. Gravity, wind and thermal static analyses were used to compute the displacements and rotations of the optical elements. These deformations were then combined with the optical sensitivity matrix. The sensitivity matrix relates displacements and rotations of the optical elements with the image motion at the focal plane. The performance of the new optical design in terms of image motion and its impact on the technical specification was made. These analyses were used for defining the specification of the preliminary design in terms of eigenfrequencies and image motion.

An accurate alignment of the optical surfaces of a telescope is essential to guarantee an optimal image quality since even small displacements introduce aberrations increasing towards the edges of the field. This effect is especially detrimental in wide-field imagers. This work proposes the derivation of a fully analytical model of the wavefront error as a function of the most likely system misalignments. An accurate response of the telescope under a predefined set of misaligned conditions is obtained through simulations in Zemax OpticStudio. The resulting data is combined through an integrated modeling approach, obtaining a map of the aberrations as a function of a vector of perturbations applied to the optical system. The analytical wavefront error allows for a quick and accurate assessment of the theoretical PSF across the entire image field. As a case study, the example of the Rubin Observatory is adopted, featuring an 8.4m primary mirror and a large field of view.

Maunakea Spectroscopic Explorer (MSE) is a massively multiplexed spectroscopic survey facility that will replace the Canada-France-Hawaii-Telescope. This 11.25-m telescope, with its 1.5 square degrees field-of-view, will observe 4,332 astronomical targets in every pointing. Fibers at the prime focus will pick up the light and transmit it to banks of low/moderate (R=3,000/6,000) and high (R=40,000) resolution spectrographs. Actuators position individual fibers in the field of view to enable simultaneous full field coverage for both resolution modes. This instrument suite, dedicated to large scale surveys, will enable MSE to collect a massive amount of data: equivalent to a full SDSS Legacy Survey every 7 weeks. A conceptual design was developed in recent years and the project is preparing for the preliminary design phase. Now is the time to do a thorough cross check of the system level performance budgets against the predicted performance of the conceptualized systems and to check their compliance against the high level science requirements. This is particularly important in light of changes in scope due to scientific revisions and to technical challenges encountered during the conceptual design phase. Areas of non-compliance will require review as to how best to mitigate the non-compliance. The results of this analysis led to issues being identified with the telescope and spectrograph concepts. This paper will summarize progress on this analysis, redesign, and trade study.

Portugal will build the warm support and access structure (WSS) to the mid-infrared, first generation ELT instrument - METIS. The particular characteristics of METIS and the ELT pose several challenges to designing the WSS according to requirements, as well challenges to the assembly and integration of the WSS. We here provide you an overview of those challenges, as well as strategies to overcome and mitigate issues related to the mass and dimensions of the WSS.

HARMONI is the first light visible and near-IR integral field spectrograph for the ELT. It covers a large spectral range from 450nm to 2450nm with resolving powers from 3500 to 18000 and spatial sampling from 60mas to 4mas. It can operate in two Adaptive Optics modes - SCAO (including a High Contrast capability) and LTAO - or with NOAO. The project is preparing for final design review (FDR). The Natural Guide Star Sensors (NGSS) system of HARMONI provides wavefront and image stabilization sensing for each of the four observing modes of the instrument, LTAO, SCAO, HCAO, and NOAO. It consists of five subsystems, three of which provide wavefront sensing (LOWFS, SCAOS and HCM), the remaining two (ESE and ISB) providing thermal and mechanical functions. To limit thermal background and to ensure the required stability, the sensors operate in a cold, thermally stabilized, dry gas environment. This paper presents the overall design of the system with emphasis on system analysis, assembly and test, and maintenance.

The US Extremely Large Telescope Program (US-ELTP) is a joint endeavor of National Science Foundation’s National Optical-Infrared Astronomy Research Laboratory (NSF’s NOIRLab) and the organizations building the Thirty Meter Telescope (TMT) and the Giant Magellan Telescope (GMT). Our goals are to complete construction of both observatories and to enable all US astronomers to carry out transformational research that takes full advantage of the diverse capabilities of both GMT and TMT as well as the two-hemisphere system. NOIRLab’s portion of this initiative is a software suite called the US ELT Program Platform (UPP). The UPP will support the investigator through all phases of their observations: from proposal creation, time allocation, observation data transfer and storage, and data analysis to publication. Among many design and development activities, NOIRLab is currently preparing for a 2023 NSF Preliminary Design Review (PDR). This is the first of a three-paper series that will discuss the initial concepts behind the US-ELTP Verification and Validation (V&V) process, how those concepts mature as we progress to the PDR and a Final Design Review (FDR, part 2), and how the V&V effort is conducted on real products during the Construction Phase of the project (part 3).

ERIS is a new instrument currently under commissioning at Cassegrain focus of ESO VLT UT4. Its mission is to replace the NAOS-CONICA and SINFONI instruments to push to the edge the capabilities of this 8-meter class telescope thanks to his AO module by take full advantage of the new DSM (Deformable Secondary Mirror) and the artificial star builder facility (4LGSF - 4 Laser Guide Star Facility). The AO module have been built trying to maximize the lifetime and reliability and to minimize the downtime. In this paper we will present the constraint we were subjected and the approach we followed to perform the RAM (Reliability, Availability, Maintainability) analysis, comparing with what we experienced up to now and the lesson learned after the assembly and integration (AIV) process.

This research effort is focused on the identification of the failure modes and the hazards linked to the control hardware of the Multi-conjugate adaptive Optics Relay For ELT Observations (MORFEO). MORFEO is a module belonging to the Extremely Large Telescope, under construction by ESO in Armazones (Chile). It is a post-focal adaptive optics module designed to help to compensate for distortion caused by turbulence in the Earth's atmosphere. In this paper the FMECA and FTA on the Instrument Control Hardware design for ELT class of instrumentation (o MORFEO ICH design) are described, starting from a functional block diagram of the system. In particular, the Instrument Control Hardware has interfaces with most other subsystems, which means that its status consequences on the rest of the system deserve special attention. This work aims to provide an analysis of the dependability of the current design configuration and to analyse the effects of potential hazards and failures, in order to define the next steps of the design to keep compliance with the upper-level RAMS requirements.

The ASTRI Mini-Array is a project of the Italian National Institute for Astrophysics (INAF) to construct and operate an observatory to study astronomical sources emitting in the TeV spectral band. The ASTRI Mini-Array is under construction and consists of an array of nine innovative Imaging Atmospheric Cherenkov Telescopes located at the Teide Astronomical Observatory, operated by the Instituto de Astrofisica de Canarias, on Mount Teide (~2400 m a.s.l.) in Tenerife (Canary Islands, Spain). In the project framework, we have implemented a Product Assurance (PA) programme, which defines the strategy and the organization for the management of the quality control. It defines the applicable quality requirements for design, procurement, AIT, and verification, and the guidelines to manage the acceptance of the deliverable items provided by the external suppliers. In the case of HW items, the PA programme provides requirements regarding the monitoring of manufacturing process and qualification activities, as well as the item identification, inspection and storage. For SW components, we have provided a dedicated Quality Assurance plan, and detailed guidelines to drive the whole software development life cycle. We paid particular attention to the management of non-conformances and requests for deviations/waivers, since these are very critical in the case of external industrial partners. In this work we present the layout and contents of the ASTRI Mini-Array PA programme, describing the organization adopted within ASTRI for its management and reporting some examples of how it has been applied up to now.

Text-based requirements management tools are widely used in engineering today. The concept behind it is quite simple, but this simplicity does not mean that these tools are affordable. In most cases, the cost of a requirements management tool license is similar to the cost of a CAD software license, the latter pertaining to a much more complex software tool. At cosmoBots.eu we have developed a plugin for a free and open project management tool (Redmine) that turns it into a powerful requirements management tool, including automatic and instant hierarchy and dependency diagrams, import/export from/to spreadsheets, full interoperability with other tools using the REST API, also including role-based lifecycle management and reporting. Several projects in IAC (EST, MICAL, NRT...) are officially using cosmoSys-Req to manage their requirements, and other projects or institutions (GTC, IACTEC...) are currently evaluating their use.

The European Solar Telescope (EST) is a 4.2-m solar telescope, based on an aplanatic Gregorian configuration with an alt-azimuthal mount. This contribution presents the status of EST and describes the baseline for the preliminary design of the Telescope Structure (Telescope Mount), Enclosure and Pier. It also introduces the systems engineering, model and tools. In addition, it explains the rationale of the main specifications. The optical design has undergone major changes since the conceptual design. The M2 Assembly has become an Adaptive Secondary Mirror, the f-number has been changed and the number of optical surfaces has been reduced to 6 mirrors and 2 lens barrels. Therefore, part of the system has been updated and new assemblies have appeared: The Transfer Optics and Calibration Assembly (TOCA) and the Pier Optical Path (POP). Some requirements make this telescope unique: the primary mirror is above the elevation axis, the multi-conjugated adaptive optics is integrated in the telescope, the telescope instrumental polarization is minimized and the telescope will observe in open enclosure configuration to improve the natural air flushing. The drawback of the open configuration is that the telescope structure, M1 and M2 will be exposed to the wind load and the thermal load by radiation, forcing the development of a stiffer Telescope Structure, a specific thermal control to achieve the pointing and tracking performances and a low local seeing degradation. The Preliminary Design phase of the Telescope Structure, Enclosure and Pier have been developed by IDOM throughout 2021 and 2022, following technical requirements by the EST Project Office.

This paper proposes the usage of IBM Engineering Requirements Management DOORS and IBM Engineering Lifecycle Optimization Publishing for system test management and reporting. DOORS is used to capture the technical requirements, test specifications and test reports as well as establishing links between the requirements and tests specifications. DOORS custom attributes capture additional information such as object type, verification methods and success criteria. Engineering Publishing interacts with the DOORS database to produce document style reports including Requirements Specifications, Test Plans, Test Reports and compliance matrixes. To illustrate the usage of these tools, data from the NIX IR Imager for the ERIS instrument is used.

MORFEO (formerly known as MORFEO) an adaptive optics module able to compensate the wavefront disturbances affective the scientific observation. It will be installed on the straight-through port of the telescope Nasmyth platform to serve the first-light instrument MICADO and with the provision for a future second instrument. The module underwent the Preliminary Design Review in 2021 and is expected to be commissioned in 2029. In this paper we present a synthesis of the System Engineering approach adopted to manage the development of the instrument. We will discuss the evolution of the architecture towards the requirements. We will detail the criticalities of the system engineering with a particular focus onto the management of the interfaces between subsystems and external systems (Telescope, other instruments…). We will also make a brief description of way in which we implemented Model Based System Engineering and the tools adopted in order to manage requirements, use cases and interfaces.

Systems Engineering requires the involvement of different engineering disciplines: Software, Electronics, Mechanics (often nowadays together as Mechatronics), Optics etc. Systems Engineering of Astronomical Instrumentation is no exception to this. A critical point is the handling of the different point of view introduced by these disciplines often related to different tools and cultures. Model Based Systems Engineering (MBSE) approach can help the Systems Engineer to always have a complete view of the full system. Moreover, in an ideal situation, all of the information resides in the model thus allowing different views of the System without having to resort to different sources of information, often outdated. In the real world, however, this does not happen because the different actors (Optical Designers, Mechanical Engineers, Astronomers etc.) should adopt the same language and this is clearly, at least nowadays and for the immediate future, close to impossible. In the Italian Astronomical Community, we are developing methodologies and tools to share the expertise in this field among the different projects. In this paper we present the status of this activity that aims to deliver to the community proper tools and template to enable a uniformed use of MBSE (friendly name Astro MBSE) among different projects (ground and space based). We will analyze here different software and different approaches. The target and synthesis of this work will be a support framework for the MBSE based system Engineering activity to the Italian Astronomical Community (INAF).

Systems Engineering requires the involvement of different engineering disciplines: Software, Electronics, Mechanics (often nowadays together as Mechatronics), Optics etc. Systems Engineering of Astronomical Instrumentation is no exception to this. A critical point is the handling of the requirements, their tracing, flow down and the interaction with stakeholders (flow up) and subsystems (flow down) in order to have traceable and methodical evolution and management. In the Italian Astronomical Community, we are developing methodologies and tools to share the expertise in this field among the different projects. In this paper we will focus on the requirement management approach among different projects (ground and space based). We will analyses here different architectures and tools in order to provide to the end user a useful tool optimized for Astronomical instrumentation. The target and synthesis of this work will be a support framework for the Requirement management of the Italian Astronomical Community (INAF) projects.

This paper presents the state-of-the-art techniques employed to manage Computer Aided Design (CAD) data at the Thirty Meter Telescope (TMT) project. It reviews the role of CAD data in relation to written interface specifications and design requirements documents; storage and access control; configuration control; verification activities; and handling of nonconformities. The process of CAD compliance verification and handling nonconformities with a closed-loop system is particularly emphasized as an important strategy for risk mitigation.

Digital twin of optical telescopes could provide high reliable models to predict the performance of the overall system during the design or the manufacture stage and could further be used to analyse faults after we build these telescopes. Comparing with conventional simulation methods, the digital twin of optical telescopes would import real test or telemetry data with machine learning algorithms and integrate numerical models with these data. As there are a lot of data to be collected, such as test data for optical elements, telemetry data from the telescope and the outer environment, it would be necessary to develop an appropriate database for digital twin of the optical telescope. In this paper, we would discuss our design of the database and use a simple example to show applications of the database.

Time domain astronomy requires continuous observations to capture series of images of celestial object. To satisfy observation requirements, scientists need to place several telescopes in different sites or in the same site to form a telescope array. In recent years, several telescope array projects have been proposed. Design of telescope arrays is quite different from that of a single telescope. We need to make trade off between the image quality, the aperture size, the field of view and the number of telescopes to satisfy the scientific requirement with minimal overall cost. In this paper, we will introduce our method to optimize the design of a telescope array which would consider detail design of telescopes as well as the overall cost for building and maintaining of these telescopes. This paper provides a useful tool for future telescope array projects.

Aiming at the lack of effective visualization strategies for the operation and maintenance of the telescope drive system, this paper proposes to use digital twin technology to improve telescope driving system visualization. Firstly, visual modeling techniques are used to construct the digital twin model of the telescope drive system. Then, the mapping relationship between the physical and digital twin of the telescope drive system is established, and the real-time mapping of the digital twin operation status is realized through the physical parameters, historical operation data and sensor data of the drive system. Finally, the intelligent operation and maintenance strategy of the telescope is formulated using the digital twin of the drive system visualization. This research will solve the visualization problems in the telescope drive system, and has practical significance for improving the operation efficiency of the telescope and formulating efficient maintenance strategies.

As the preliminary step of the fault injection, the way of fault sample selection has a significant influence on the testing result. In order to promote the efficiency as well as to guarantee the correctness, a theoretical framework for fault sample selection for telescope drive control system based on the SDG (Sighed Digraph) modeling and the importance of nodes in graph theory is proposed in this study. Firstly, the SDG model is developed qualitatively according to the mathematical equations of control loops utilizing classic control methods. Secondly, the compatible pathways are introduced which can depict the fault propagation completely and the importance of the model nodes based on destroying degrees relative to the components of the drive control system are introduced. Finally, a procedure of fault sample selection method is proposed to show an efficient result which only needs a few of fault samples and data information.